Recent stringent Government regulations pertaining to safety and health in industry (OSHA) create an urgent need for complying equipment and instrumentation in many areas. In connection with stationary oil field equipment, such as engines and compressors, there is a requirement for a combined device to automatically maintain the proper crankcase oil level and to automatically shut down the engine or compressor following depletion of the usual gravity supply of oil below safe limits. In providing the automatic machine shut-down feature in compliance with existing regulations pertaining to hazardous locations, an explosion-proof chamber must be provided for all electrical contact or switching means.
It is the objective of the invention, therefore, to provide a combination-type instrument for the above purposes which will be in full compliance with all private and Government safety regulations and, in particular, OSHA regulations pertaining to oil field equipment.
It is a further object of the invention to provide an instrument of the mentioned type having additional novel features including the provision of a float position monitoring pointer within the explosion-proof chamber and behind a safety glass panel for that chamber. Additionally, the invention provides a convenient external sight gage allowing the level of oil in the float chamber to be directly observed, the sight gage reading being indicative of the oil level in the crackcase of the machine to which the invention is applied.
Another important feature of the invention is the provision of a sealed rotary shaft between the oil filled float chamber of the instrument and the explosion-proof chamber in which the pointer and associated ignition cut-off switch or equivalent pneumatic valve means is arranged.
The instrument which includes all of these features possesses compactness, sturdiness, ease of assembly and disassembly, and relative low cost of manufacturing.
The prior patented art contains certain teachings relative to automatic devices for maintaining lubricating oil levels in engines and the like and for shutting down such machines when the oil level is below safe limits. Examples of the patented prior art are U.S. Pat. Nos. 1,280,222 and 2,903,091. These patented devices do not have the ability to comply with existing safety regulations and do not possess explosion-proof chambers for their electrical contacts or switching means and neither do they possess the combined capabilities of the present invention for performing a number of monitoring and control functions at one time. Thus, the present invention is deemed to be a distinct improvement on the known prior art and such improvement or advancement in the art constitutes a further objective of the invention.
Other features and advantages of the invention will become apparent during the course of the following description.